TEC system help?

Hello,

I find myself in charge of a small grocery store with a TEC system. Everyone there seems to be using the system by routine without really knowing much about it, so I need to learn as much as possible. I've tried Google without success. The registers are TEC M-2800-48P-7RD-Z. They are connected to a computer by interface devices marked TEC FC-62 and TEC FC-71. The computer is running a DOS program, the main screen has a heading of TEC M-2300-45 Manager Console Version 2.3F. The program is simply called mcs.exe. I realize the system is old, but we can't afford to replace the registers. However I could replace the computer as I have a spare sitting around. If anyone could point me to a manual for the registers, the software, or info for the interface devices I would really appreciate it. I am especially interested in gaining the ability to extract and analyze price data.

Thanks,

Bob